Iodoform, also called triiodomethane, a yellow, crystalline solid belonging to the family of organic halogen compounds, used as an antiseptic component of medications for minor skin diseases.

First prepared in 1822, iodoform is manufactured by electrolysis of aqueous solutions containing acetone, inorganic iodides, and sodium carbonate. Several reagents convert iodoform to methylene iodide (diiodomethane), a dense liquid, colourless when pure but usually discoloured by traces of iodine, used as a heavy medium in gravity separation processes.

Iodoform’s antiseptic action, discovered in 1880, made it an important medicinal, but it has been largely displaced by more effective substances.